System and method for pumping intravenous fluid

Abstract

An intravenous fluid pump (IV) contains a disposable part including a fluid chamber having a resilient top membrane and a non-disposable part including a piston abutting a resilient membrane and a vacuum chamber fitted on top of the resilient top membrane. An external pump is used to create vacuum in the vacuum chamber, resulting in the resilient top membrane being held taut. The flow rate through the pump is relatively independent of changes in the pressure of IV fluid on the upstream and the downstream due to changes in the relative elevation of the fluid reservoir and the patient with respect to the fluid pump.

1. A system for delivery of intravenous fluid, comprising:
 a disposable portion in contact with the intravenous fluid during delivery of the intravenous fluid; and 
 a non-disposable portion isolated from contact with the intravenous fluid during delivery of the intravenous fluid; 
 wherein: 
 the disposable portion comprises:
 a fluid chamber having an opening; and 
 a pumping membrane positioned to form a side of the fluid chamber; and 
 
 the non-disposable portion comprises:
 a sealing membrane; and 
 a vacuum chamber formed between the sealing membrane and the pumping membrane, the vacuum chamber comprising an opening sealable airtight during the delivery of the intravenous fluid. 
 
 
     
     
       2. The system of  claim 1 , further comprising a vacuum source for removing air from the vacuum chamber. 
     
     
       3. The system of  claim 1 , wherein the disposable portion is configured to be able to attach to the non-disposable portion with an airtight connection. 
     
     
       4. The system of  claim 1 , wherein the non-disposable portion further comprises a piston comprising a piston shaft and a piston head extending through the sealing membrane. 
     
     
       5. The system of  claim 1 , further comprising:
 an inlet tube in fluid contact with the opening, the inlet tube having an input valve; and 
 an outlet tube in fluid contact with the opening, the outlet tube having an output valve; wherein 
 the input valve is configured to allow passage of fluid into the fluid chamber when the piston is moving outwards; and 
 the output valve is configured to allow passage of fluid from the fluid chamber when the piston is moving inwards. 
 
     
     
       6. A fluid delivery apparatus comprising:
 a fluid chamber; 
 an inlet valve controllably coupling the fluid chamber to an inlet tube; 
 an outlet valve controllably coupling the fluid chamber to an outlet tube; 
 a pumping membrane defining at least one portion of the fluid chamber; 
 a sealing membrane positioned to form a vacuum chamber between the pumping membrane and the sealing membrane; 
 an opening in the vacuum chamber, the opening sealable to make the vacuum chamber airtight during operation of the fluid delivery apparatus; and 
 a piston positioned against the pumping membrane and configured to reciprocate against the pumping membrane to reduce and expand the fluid chamber and thereby pump fluid in and out of the fluid chamber. 
 
     
     
       7. The fluid delivery apparatus of  claim 6 , wherein the input valve and the output valve are configured to prevent simultaneous flow of fluid in and out of the fluid chamber. 
     
     
       8. The fluid delivery apparatus of  claim 6 , wherein
 the input valve is configured to allow fluid to enter the fluid chamber when the piston is being pulled outwards; and 
 the output valve is configured to allow fluid to exit the fluid chamber when the piston is being pushed inwards. 
 
     
     
       9. The fluid delivery apparatus of  claim 6 , wherein the vacuum chamber further comprises:
 a sealable opening for drawing air out to create vacuum in the vacuum chamber. 
 
     
     
       10. The fluid delivery apparatus of  claim 6 , wherein the piston is further coupled to the sealing membrane. 
     
     
       11. The fluid delivery apparatus of  claim 6 , wherein the sealing membrane is configured to move with the piston and maintain a reduced pressure in the vacuum chamber.